Added timestamp format "epoch-usec"

This timestamp format will print the seconds since epoch along with
subdivision in microseconds.

Example:
 [1748009585.087083] tio v3.9-8-g2fb788f-dirty
 [1748009585.087156] Press ctrl-t q to quit
 [1748009585.087683] Connected to /dev/ttyUSB0

man/tio.1.in

@@ -150,6 +150,8 @@ Set timestamp format to any of the following timestamp formats:
 ISO8601 format ("YYYY-MM-DDThh:mm:ss.sss")
 .IP "\fBepoch"
 Seconds since Unix epoch (1970-01-01)
+.IP "\fBepoch-usec"
+Seconds since Unix epoch (1970-01-01) with subdivision in microseconds
 .PP
 Default format is \fB24hour\fR
 .RE

man/tio.1.txt

@@ -116,6 +116,8 @@ OPTIONS
 
               epoch           Seconds since Unix epoch (1970-01-01)
 
+              epoch-usec      Seconds since Unix epoch (1970-01-01) with subdivision microseconds
+
               Default format is 24hour
 
            --timestamp-timeout <ms>

src/bash-completion/tio.in

@@ -89,7 +89,7 @@ _tio()
             return 0
             ;;
         --timestamp-format)
-            COMPREPLY=( $(compgen -W "24hour 24hour-start 24hour-delta iso8601" -- ${cur}) )
+            COMPREPLY=( $(compgen -W "24hour 24hour-start 24hour-delta iso8601 epoch epoch-usec" -- ${cur}) )
             return 0
             ;;
         -c | --color)

src/configfile.c

@@ -207,7 +207,7 @@ static void config_parse_keys(GKeyFile *key_file, char *group)
     config_get_bool(key_file, group, "timestamp", (bool*) &option.timestamp);
     if (option.timestamp != TIMESTAMP_NONE)
     {
-        config_get_string(key_file, group, "timestamp-format", &string, "24hour", "24hour-start", "24hour-delta", "iso8601", "epoch", NULL);
+        config_get_string(key_file, group, "timestamp-format", &string, "24hour", "24hour-start", "24hour-delta", "iso8601", "epoch", "epoch-usec", NULL);
         if (string != NULL)
         {
             option_parse_timestamp(string, &option.timestamp);

src/options.c

@@ -400,6 +400,10 @@ const char* option_timestamp_format_to_string(timestamp_t timestamp)
             return "epoch";
             break;
 
+        case TIMESTAMP_EPOCH_USEC:
+            return "epoch-usec";
+            break;
+
         default:
             return "unknown";
             break;
@@ -430,6 +434,10 @@ void option_parse_timestamp(const char *arg, timestamp_t *timestamp)
     {
         *timestamp = TIMESTAMP_EPOCH;
     }
+    else if (strcmp(arg, "epoch-usec") == 0)
+    {
+        *timestamp = TIMESTAMP_EPOCH_USEC;
+    }
     else
     {
         tio_error_print("Invalid timestamp '%s'", arg);

src/timestamp.c

@@ -75,6 +75,7 @@ char *timestamp_current_time(void)
             len = strftime(time_string, sizeof(time_string), "%Y-%m-%dT%H:%M:%S", tm);
             break;
         case TIMESTAMP_EPOCH:
+        case TIMESTAMP_EPOCH_USEC:
             // "N.sss" (seconds since Unix epoch, 1970-01-01 00:00:00Z)
             tv = tv_now;
             tm = localtime(&tv.tv_sec);
@@ -84,12 +85,18 @@ char *timestamp_current_time(void)
             return NULL;
     }
 
-    // Append milliseconds to all timestamps
+    // Append millis-/microseconds to all timestamps
     if (len)
     {
-        len = snprintf(time_string + len, TIME_STRING_SIZE_MAX - len, ".%03ld", (long)tv.tv_usec / 1000);
+        if ( option.timestamp == TIMESTAMP_EPOCH_USEC )
+        {
+           len = snprintf(time_string + len, TIME_STRING_SIZE_MAX - len, ".%06ld", (long)tv.tv_usec);
+        }
+        else
+        {
+            len = snprintf(time_string + len, TIME_STRING_SIZE_MAX - len, ".%03ld", (long)tv.tv_usec / 1000);
+        }
     }
-
     // Save previous time value for next run
     tv_previous = tv_now;
 

src/timestamp.h

@@ -29,6 +29,7 @@ typedef enum
     TIMESTAMP_24HOUR_DELTA,
     TIMESTAMP_ISO8601,
     TIMESTAMP_EPOCH,
+    TIMESTAMP_EPOCH_USEC,
     TIMESTAMP_END,
 } timestamp_t;
 

src/tty.c

@@ -1100,6 +1100,9 @@ void handle_command_sequence(char input_char, char *output_char, bool *forward)
                     case TIMESTAMP_EPOCH:
                         tio_printf("Switched timestamp mode to epoch");
                         break;
+                    case TIMESTAMP_EPOCH_USEC:
+                        tio_printf("Switched timestamp mode to epoch with subdivision in microseconds");
+                        break;
                     case TIMESTAMP_END:
                         option.timestamp = TIMESTAMP_NONE;
                         tio_printf("Switched timestamp mode off");